"During the API category development process, the technology team for Shell Rotella designed our CK-4 engine oils to surpass the specification requirements so that they can meet or exceed the needs of different engine and vehicle manufacturers," said Dan Arcy, global OEM technical manager of Shell Lubricants. "We have worked closely with Ford to demonstrate that Shell Rotella engine oils meet the WSS-M2C171-F1 specification and provide the protection they require."

In March, Ford recommended a formulation from its parts division, Motorcraft, instead of other CK-4 or FA-4 oils that could cause damage to the engine.

Shell Lubricants spent more than five years developing and testing their CK-4 specification heavy-duty engine oils, which have been tested over more than 45 million miles. The new Shell Rotella CK-4 formulations provide superior wear protection compared to Shell Rotella legacy CJ-4 formulations, according to Shell.